Process and apparatus for the production of sounds of any desired tone color



Dec. 12, 1933.

, H. KNEMANN 1,939,355 PROCESS AND APPARAI'USl FOR THE PRODUCTION OF SOUNDS OF ANY DESIRED TONE COLOR `F11ed Aug. 51, 1951 2 Sheetsheet 1 j www Dec. l2, 1933.

H. KNEMANN PROCESS AND APPARATUS FOR 'THE PRODUCTION OF SOUNDS OF ANY DESIRED TONE COLOR Filed Aug. 3l, 1951 2 Sheets-Sheet 2 a J ma Y f Iol HU lol H. Imi H. .lol H.. |O| HU lOl H ICI. D Qa, HT @ha H D U l Patented 12, 1933 UNITED STATES- PROCESS AND APPARATUS FOR THE PRO DUCTION OF SOUNDS' OF ANY DESIRED TONE COLOR Heinrich xnemann, Munster, Germany Application 6 Claims.

This invention relates to improvements in musical instruments 4and more particularly concerns an instrument in which a tone of any desired color or timbre may be produced.

It is well known that the tone color or timbre of a particular musical instrument depends upon the ratios of the amplitudes of the fundamental and overtones. Thus with a flute, for example, the amplitude of the fundamental may be fifty or more times greater than the amplitude of one of the overtones. It has been difficult heretofore to produce synthetically, say, by means of lip pipes, a mixture of the fundamental and overtones in which the proper ratio of amplitudes of the several tones is present. On the one hand if the fundamental is produced at the proper amplitude, then no sound is produced when the overtone pipes are blown at such a reduced amplitude that the amplitude of the overtone is but one 50th part of the amplitude of the fundamental tone. If on the contrary, the overtones `are produced with the desired amplitudes, and it is sought to producev a fundamental with an amplitude fifty times as great as the latter, the pipe of the fundamental is overblown, i. e., it no longer ygives a pure sinusoidal vibration and the final mixture does not have the desired tone color. The same is true of other instruments.

According to the present invention, the individual acoustic vibrations are produced at a; suitable amplitude for` the lip pipes or other devices which are commonly employed in producing these tones. Each device is so tuned to give its particular pitch, and these pitches are so arranged with respect `to one another as to provide the fundamental and the desired overtones for a succession of tones in the chromatic or other scale at their most suitable amplitudes for mechanical production of tones. The acoustic vibrations are then converted into electrical oscillations and in this condition brought by resistances being inserted to an amplitude suited for the tone color desired, and are mixed to produce a complex of electrical oscillations, which after amplification to the desired degree, are re-converted into acoustic vibrations of the desired strength.

The invention, however, although illustratively described hereinafter as employed with lip pipes, is not so limited, as other tone producing devices such as tuning forks, reeds, or the like may be employed for producing electric currents of the prescribed frequencies.

In the drawings is set forth one example of execution of a musical instrument according to this invention in which lip pipes yare employed for the production of the sounds of a tone color desired.

In these drawings:

Fig. 1 diagrammatically shows the arrange- Aumt 31, 193'1, serial No. 560,475, d in Germany August 30, 1930 ment of the pipes andv their keyboard in perspective.

Fig. 2 the same in a diagrammatic plan.

Fig. 3 a vertical sectional view showing the connections of a. key with pipes, and the device for converting the acoustic vibrations into electrical oscillations.

Fig. 4 diagrammatically the arrangement of the electrical parts of the instrument.

The instrument comprises a plurality of lip ory organ pipes arranged in series such that each series has a pipe delivering the fundamental, and other pipes delivering the desired overtones corresponding to this fundamental. When the corresponding key is depressed, all the pipes of this series are blown. In the drawings, the instrument is illustrated as being provided with pipes in each series for delivering the fundamental and the first four overtones. Each series corresponds to one step. in the chromatic scale, for example. Thus when the key ai is depressed (Figs. 2 and 4) the pipes b1", bi1, bf2, bi3 and hr4 are sounded. Similarly, when the key a2 is depressed, the pipes 192, 17212222, U23 and br* are sounded and similarly for the remaining .keys and pipes. It will be understood that although devices for producing only the first four overtones are shown, any desired number of such overtone device may be provided.

Since each of the series is preferably identical in construction, save for the size of the pipes therein, an illustrative` form of construction for the link 11 to theleft and Worked the crank 12 to open the valve 13 leading from the wind chest 14 into the pipe B0, so that this pipe sounds with the fundamental tone corresponding to the key a. At the same time, the movement of the key has raised the rod 15 and rocked the lever 16 whereby to withdraw the damper 17 from the diaphragm C and the latter sounds in resonance with the air column in the pipe B0, for which purpose it is made of a suitable thickness and material with respect toits diameter in well known manner. A cap 18 is arranged on the pipe B, in which is supported a permanent magnet d having a winding E thereon connected to the electrical leads 19. For clearness of the drawings, this cap is illustrated on top of the lip pipe, although obviously this is not essential to the invention so long as a sufiicient movement of the responding element such as the diaphragm C. It is preferred to provide an adjustable stop K in each pipe to restrict the cross section through which the air column in the pipe B operates upon the diaphragm C. Y

The link 11 also leads to a crank lever 20 which in turn is connected to a link 15a to a lever 16a operating in a second pipe B1. The wind chest 14a likewise contains a valve 13a operated bythe link 11 so that the second pipe B1 is also sounded when the key a is depressed. The cap 18a of this pipe B1 likewise contains an electromagnet and the diaphragm and stop arrangement is provided as with the pipe B0, so that upon the sounding of the pipe B1, an electrical oscillatory current passes in the external leads 19a and is of the frequency of pipe B1.

The sarne'construction is employed for each of the other pipes in each of the other pipes in each series, so that upon depression of a given key A, the fundamental and overtones are sounded which correspond thereto, and sinusoidal a1- ternating currents are produced in the corre'- sponding external leads. Further, each of the series is similarly constructed. All of the external leads of the fundamental pipes b1", D20, Z230 bito (Fig. 2) are connected in parallel (Fig. 4).

connectedin parallel. Hence, asshown in Fig. 4, the coils e1", e2, es", el e100, are connected to the input winding of a transformer f, which has a corresponding secondary winding 30 connected to apotentiometer resistance g. A tap connection 31 onvthis resistance is connected through a condenser 32 with a bus Wire 33 which is connected to an input condenser 34 with the grid of an input amplifying tube h, which is provided, for example, with the usual input resistance W and has cathode energizing batteries 35 and the anode or spaced current battery 36. A second stage ha is connected in cascade, and further amplies the current and delivers it to a loud speaker i.- A variable resistance 37 is connected in shunt 'of the input resistance of the first tube h, and may be operated by a control handle 38 preferably located adjacent the keyboard, Whereby to vary the volume of the sound mixture composed of fundamentals and overtones to be delivered from the loud speaker i. Also, it is preferred to provide a handle 39 adjacent the keyboard for controlling the tap connection 31 on the potentiometer resistance g by which the .amplitude of the current received from the pipe devices corresponding to the fundamental tones may be regulated.

Similarly, the respective overtones have their coils er1, er1, e341 the input winding f1 of a transformer having an output winding 30a connected to a potentiometer resistance g1 with the variable tap connection 31a controllable by a handle 39a adjacent the generated in any coil E shall not pass for toov great an extent through the other coils in parallel thereto, but will pass ythrough the proper transformer, the resistance of the individual coils is preferably high with respect to the resistance of the 'transformer itself.

The pipes are each constructed in the manner well known to those skilled inthe organ building y Similarly, all of the external leads for the first, second, third and fourth overtones are parallel and are in series to By suitable variation of the controlart, to give their own fundamental tones only, while permitting the overtones to sound not at all or only very weakly for each of the pipes.

If special purity is desired, and' the pipe does not render its fundamental tone with suicient freedom from 'overtones the space between the stop K and the diaphragm may be dimensioned as a resonator responding to the fundamental tone.

i It will be noted that the dampers 1'7, which rest against the corresponding diaphragm C when the keys a are in the upper or nondepressed position, prevent any substantial movement of the respective diaphragms C. Hence, when any key is depressed, the first overtone or octave vibration, etc., which may occur will not operate through the corresponding octave pipe etc., to produce a vibration of the diaphragm of this octave pipe etc., and thus lead to movements of v the air column in this pipe, and hence by resonance cause an undesired amplitude of this rst overtone, nor produce any vibration of other pipes which might lead to beat notes. By this construction, only the diaphragms are permitted to move which are released by their respective 'dempers upon the depression of the respective keys.

The manual controls 39, 39a may be comprised in a mixing or playing board, to form a tone color keyboard so that the tone color may be changedv not only occasionally during a piece of music as can today be accomplished by the playing of different musical instruments flute, violin, horn etc. at proper times, but also during the same chord, the change of tone color may be made. In other words, playing may be done not only by selecting the fundamental pipes andl overtones to form chords, but also the tone color may be changed in a similar manner and at the same time. The tone strength is controlled by the handle 38, or by other adjustment of the amplifying system in known manner.

The'tone colour or timbre keyboardmay be constructed in a manner differing from that .indicated in Figure 1 by theihandles 39, 39a for example, as in the construction shown in `vFigures 5 to 7 or in that shown in Figures 8 to 10, and is then preferably arranged adjacent the keyboard a1-a10 instead of above it.

Preferably, the tone color or timbre keyboard is arranged not directly above the keyboard a1 to a10 (Figure 1) but on, say, the right hand side of the instrument as will be seen in Figure 1, so

that the two players, one of whom plays on the keyboard a1 to al, while the other plays on the timbre keyboard 38 and 39 to 39c, will not disturb one another.'

Preferably, the organ or lip pipes of Fig. 1 are enclosed by a housing 100 shown in dotted lines in Fig. 1 to prevent the sounds from conflicting with the sounds produced by the loud speaker i, in the event that the keyboard and the loud speaker are located close to one another.

It is obvious that the invention is not limited to the form of construction shown, but that many changes may be made therein with respect to the means of generating the vibrations of individual pitch, and in the means oi' selecting th'e 'amplitudes of fundamental and overtones which are to be mixed, and all without departing from the scope of the invention.

What I claim is:

1. Method of producing sounds of any desired tone-color, which comprises individually produc- 1118 acoustic vibrations which are the fundamentals and overtones of a plurality of different pitches, causing said vibrations independently to produce resonance in individual air columns at the fundamental frequency of each thereof whereby to purify the vibrations individually, converting the purified acoustic vibrations individually into electrical oscillatory currents, controlling the amplitudes of the oscillatory currents with respect to one another to obtain a predetermined ratio of amplitudes of a fundamental and its overtones with respect to one another, mixing the currents, and reproducing acoustic vlbrations from the mixed currents.

2. Apparatus for producing sounds of any desired tone-color, comprising pluralities of means for producing acoustic vibrations of different pitches which in each plurality include individual devices for producing the fundamental and overtones ofga particular pitch and means for individually purifying said vibrations by acoustic resonance and individual converting means operated by the purified vibrations of each purifying means for converting the same into electrical oscillations, means for simultaneously operating the devices in each plurality. means common to all the fundamental, to all the first, to all the second and to all of each group of other overtone converting means for combining the electric currents of said oscillations whereby to produce individual combined electric currents each comprising the fundamental, first, second or other overtone corresponding to all the vibration producing means being operated, means for controlling the amplitudes of said individual electric currents, means for mixing all the said controlled currents to produce a mixed current, and a sound reproducing device actuated by said mixed current.

3. Apparatus for producing sounds of any desired tone-color, comprising pluralities of means for producing acoustic vibrations of different pitches which in each plurality include individual devices for producing the fundamental and overtones of a particular pitch and means for individually purifying said vibrations by acousticresonance and individual converting means operated by the purified vibrations of each purifying means for converting the same into electrical oscillations, a keyboard including keys which each simultaneously operate the devices in each plurality, meansv common to all the fundamental, to all the first, to all the second and to all of each group of other overtone converting means for combining the electric currents of said oscillations whereby to produce in` dividual combined electric currents each comprising the fundamental, rst, second or other overtone corresponding to all the vibration producing means being operated, means connected to each said common means for independently controlling the amplitudes of said individual electric currents whereby to vary the amplitudes of the fundamental and vovertone oscillations with respect to one another during playing, means for mixing all the said controlled currents to produce a mixed current, and a sound reproducing device actuated by said mixed current.

4. Apparatus for producing sounds of any d sired tone-color, comprising pluralities of devices each including a lip pipe and a diaphragm vibrated by the air column in the pipe whereby to produce acoustic vibrations of different pitches which in each plurality include individual devices for producing the fundamental and overtones of a particular pitch and a vibration dampener for said diaphragm, means for simultaneously operating the devices in each plurality and including means for moving the dampener away from the diaphragm for each selected pipe while leaving the dampeners of non-selected pipes in contact with the diaphragms whereby to prevent interference and beating by acoustic and electrical resonance, individual converting means connected to each device for converting the acoustic vibrations into electrical oscillations, means common to all the fundamental, to all the first, to all the second and to all of each group of other overtone converting means for combining the electric currents of said oscillations whereby to produce combined electric currents each comprising the fundamental, first, second or other overtone of all the vibration producing means being operated, separate means connected vto each said common means for independently controlling the amplitudes of said combined electric currents, means for mixing all the said controlled currents to produce a mixed current, and a sound reproducing device actuated by said mixed current.

5. Apparatus for producing sounds of any desired tone-color, comprising pluralities of means for producing acoustic vibrations of different pitches which in each plurality include individual lip pipes for producing the fundamental and overtones of/a particular pitch, means for simultaneously operating the lip pipes in each plurality, and individual converting means connected to each lip pipe for converting the acoustic vibrations thereof into electrical oscillations, means common to all the fundamental, to all the first, to all the second and to all ofeach group of other overtone converting means for combining the electric currents of said oscillations y whereby to produce individual combined elec tric currents each comprising the fundamental, first, second or other overtone corresponding to all the vibration producing means being operated, means connected to said common means for controlling the amplitudes of said individual electric currents, means for mixing al1 the said controlled currents to produce a mixed current, a 130 sound reproducing device actuated by said mixed current, and a sound-proof housing enclosing all said lip pipes for preventing the interference of sounds coming directly from the lip pipes with sounds coming from the said reproducing device.

6. Apparatus for producing sounds of any desired tone-color, comprising pluralities of means for producing acoustic vibrations of different pitches which in each plurality include individual devices for producing the fundamental and overtones of a particular pitch; means for simultaneously operating the devices in each plurality, and individual converting means. connected to each device for converting the acoustic vibrations into electric oscillations, pairs of conductors for connecting the converting means for the fundamentals, the firsts, the seconds, and each group of other overtone converting means in multiple for combining the electric currents of said oscillations whereby to produce individual combined electric currents each representing the fundamental, first, second or other overtone from all the vibration producing means being operated, individual current limiting means connected toA said conductors, means for mixing all said combined and limited currents to produce a mixed current, and a sound-reproducing device actuated by said mixed current.

HEINRICH KNEmNN. 15o 

